The primary thrust of this work will be to evaluate the role of bacterial surface components and salivary proteins in the adherence of acidogenic streptococci and Actinomyces species to the tooth surface. Specific inhibition of adherence will be studied using each of the components obtained in a purified and characterized form. The specific aims of this work will be to: 1) Isolate, purify and characterize the binding components of Streptococcus sanguis, Streptococcus mitior, Actinomyces naeslundii, and Actinomyces viscosus. 2) Utilize these components and radiolabeled bacteria to analyze the site-specific interactions which result in the selective adherence of these oral bacteria to enamel powder and hydroxyapatite. These studies will be carried out in the presence and absence of a salivary pellicle. 3) Analyze the effectiveness of a variety of entities (compounds which may bind to these purified binding components based on their known chemical structure) which might inhibit the colonization of the individual microbe on the tooth by blocking specific reactive sites of the components involved in adherence. The ultimate goal of this study will be to uncover useful inhibitors of the basic adherence processes which lead to the formation of dental caries and periodontal disease.